two 6's... CP's MAC's

They have been scheduled to be scrapped...or already have been.

 

A shame.

 

Mark

EMD's MAC's... all of them, from the earliest SD60MAC's(i.e. test bed BN 9503); the still hard working coal haulers - BNSF's SD70MAC's; the 5000 horse 80's; the toned down 9043's; and, the final batch of SD90MAC-H's... these were/are some of my favorite North American freight motors.

 

 

Rick

That is interesting.

 

While I have never been a fan of EMD's (visually), the Conrail SD-80MAC did draw me to that physical platform(SD-80, SD-90/43 and SD-90MAC-H). IMHO, the Conrail scheme fit them the best. Followed by CP.

 

It is a shame that the 6000 HP configuration didn't work out for either manufacture here in the states. While EMD  may have been new to the four cycle arrangement, initial testing looked good for the engine and the units. If I have read correctly though, they are still being produced and refined for use in China and I believe Australia (someone please correct me if I am wrong). Maybe somewhere down the line the need for them here will arise again. (We can dream, right? )

 

Beyond that, the other MAC's keep on earning their keep.

I still think there's a place, here, in North America, for individual 6000hp packages; DPU type technology... working with 6000hp units, seems like a good fit - for today's freight trains.

 

 

Rick

Obviously nobody in railroad management, nor the locomotive manufacturers, agree with you!

I think I read somewhere that one thing against these engines was that there was too much HP tied up in a single engine. Reduces flexibility. Among other things, it gives fewer options for combining power for specific needs. Also, if one engine goes down for repair, you've lost a lot of available horsepower in a single swoop.

 

One great advantage diesels had over steam engines, and a big selling point to the railroads when diesels were first introduced (in the form of the EMD FT demonstrators), was that they could be combined as needed to increase or decrease power depending on need (A, A-A, A-B-A, A-B-B-A, etc.). That kind of flexibility is lost as you ramp up single locomotive diesel engine sizes. 

I've mentioned this before, re: horsepower...

 

CP used to run their coal trains with six 3000hp units; 3 up front and 3 placed mid train. Nowadays, they run 4400hp units; usually, one up front, one mid train and one... at the rear.

 

Using 6000hp per unit, you could run the same 1-1-1 configuration and increase each segments number of cars, appropriately. 6000hp equipment is being used in other jurisdictions... outside of North America.

 

Even better, go with a 2-1-1 or 1-1-1-1 combination; build the train accordingly... that best utilizes 6000hp equipment; should a unit need to come off line, the remaining power has got you covered.

 

I don't think trains have reached their limit, re: the number of cars...

 

One unit doing the job of two or more, cuts down on maintenance, fuel...

 

 

Electric six's would be even better; but, that's another topic...

 

 

Rick

That may be true. At any rate, though, a major downside that I read about was concern that, as a simple example, if you have 2 6000 HP engines and one breaks down, you're stuck, and a blocked line results. If you have 4 3000 HP engines and one breaks down, you can still keep the train moving.

 

I also read about concerns that there is just not enough pulling power to go with the horsepower on these engines, and that no Class I railroad runs their trains with that high an engine power to weight ratio. With the grades experienced on most American railroads, the usefulness of these engines may be somewhat limited. At least some of time, the additional horsepower is wasted.

 

Given these considerations, it may be likely that three modern 4000 HP engines have superior adhesion to what 2 6000 HP engines can provide. But I'm certainly no expert - just repeating some things I read about the lack of acceptance of these engines.

 

Europe and parts of Asia, for example, work with significantly higher horsepower freight locomotives, as compared to the mid 4000hp range units operating, here.

 

They effectively deal with all the issues you raised...

 

There are newer models working, that utilize over double our top-end horsepower.

 

I think transcontinental corridors that see high usage, and  routes where companies want/need to increase their traffic volume... those would make good starting points, for using higher horsepower equipment.

 

 

Rick

Why was it that the SD80MACs we so successful on Conrail, and the 90MACs seem to be worthless junk?

Many reasons, but two primary reasons:

 

1) The big 6000HP 4 stroke cycle prime movers were simply way too high tech. for the average RR mechanical personnel to understand, maintain, and repair/overhaul. The even required highly specialized tooling. The SD80MAC however, had the tried and proven EMD 710 2 stroke cycle prime mover, even if it was a 20 cylinder. Unlike the early "issues" with the 20-645E3 prime mover in the SD45, the 20-710G series prime movers were VERY successful.

 

2) The "perceived need" for 6000HP diesel electric freight locomotives never panned out!

From what I've heard, GE and EMD rushed the production of  their 6000hp models...

they were trying to capture the high horsepower market. Both companies best efforts probably never made it to the marketplace... rushed, unrefined, problematic models did.

 

Since then, both companies have improved their current 6000hp prime movers and the the technology...

 

Re: the SD80MAC's - I heard they were good models; but, 6 was the magic number... the goal... back then.

 

Both, the SD80's and the 90's would have been expensive... to run; the current six's are more fuel efficient...

 

 

Rick

 

 

BTW,

 

 

there was another 5000hp model competing, during the North American high horsepower race -

 

http://en.wikipedia.org/wiki/MK5000C

 

http://www.youtube.com/watch?v=rSQR-26tQWg

 

 

Rick

 

http://www.railpictures.net/viewphoto.php?id=221948

 

 

Nice!

 

 

Rick

Rick,

 

The forgotten 'contender' when the last horsepower race started.

 

I believe the MK5000's suffered in the same manner that the SD90MAC-H and AC6000. A lot of additional technology that was being developed and unproven at the time. (And, some would say, going with DC traction instead of AC traction. But, MK was targeting them for high speed intermodal, not drag era freight. Their proposed MK5500 and MK6000 would have been AC traction.)

 

IMHO, The Phase II locomotives delivered to the UP looked Fantastic in the blue, gray and gold lettered scheme.

 

It does take some time to work out the bugs in new technology. All of the early manufactures of diesel-electrics had some sort of issue(s) to work through.

 

Whether or not these larger locomotives(SD90MAC-H and AC6000) ever make a come back here, I am sure that EMD and GE will refine their entries into reliable products.

 

Hi Henry,

 

I think the early 6000hp contenders time has come and gone; but, new, better, high horsepower models... just might have a future in North America.

 

 

Rick

 

 

 

That begs for more explanation.  Clearly there were definite reasons the 6000HP units didn't fit in with the needs of American railroads. Perhaps one reason was that the wide variety of loads and tonnage that U.S. railroads experience made single high-horsepower engines too limited in their applications, and gave fewer options for meshing the right power to mate with different load tonnages and types of loads. Perhaps, too, the newer technology, including improved adhesion, gave 4400HP engines most of what the railroads needed without the need for higher horsepower. (Not sure, just thinking out loud. It would be interesting to know the actual reasons for the railroads' rejection of these.)

Well Mr. breezinup, I'll tell a little story and let you and everyone come to your own conclusions.

 

Early on in the 6000 HP development/race, CONRAIL decided to have a consulting engineering study done on their entire system. A well know Industrial Engineering firm was contracted, and after about a year of studying the entire CONRAIL system, traffic patterns, terrain, etc. the consultant recommended that the locomotive BEST SUITED for the vast majority of main line traffic, would be blocks of six axle, high adhesion, 5000HP units. The rest of the railroad industry managers laughed at the CONRAIL management when the study was released, and a locomotive order was placed with EMD for the "newly developed" SD80MAC!

 

So, now you know the rest of the story. All the other railroad managers that put their eggs in the 6000HP basket (you will note that BNSF was one that did NOT), had to eat crow. The SD80MAC proved to be the RIGHT locomotive for both heavy haul AND TOFC/COFC main line service. The subsequent 4400/4500HP units of today are essentially a duplicate concept that was pioneered by CONRAIL.

I guess I'm just curious about the actual reasons that a 5000HP engine worked out (and now 4400HP and 4500HP), but upping the ante to 6000HP didn't work. What was it about that extra 1000HP that created an engine that "didn't pan out," as you said. Why was a 5000HP locomotive, and now 4400 and 4500HP, better suited for use? I imagine the answer is fairly complicated, involving a lot of technical factors. I suppose fuel consumption issues were involved, among others.

In general terms the 6000HP "blocks of power" wound up to be overkill.  For example, taking the CONRAIL motive power study "model", a train requiring higher horsepower per ton ratios like TOFC/COFC, generally needed either 10,000 or a max of 15,000 HP to operate from New York to Chicago without refueling.

 

However, with 6000HP motive power blocks, you got a total of of either 6000HP, (not near enough), or 12,000HP (not quite enough) or 18,000HP which was WAY too much, for the same horse power per ton ratios required, using 5000HP blocks.

 

http://www.rrpicturearchives.n...ture.aspx?id=2646085

 

http://www.rrpicturearchives.n...ture.aspx?id=2646088

 

http://www.rrpicturearchives.n...ture.aspx?id=2203740

 

http://www.railpictures.net/vi...id=151292&nseq=4

 

http://www.railpictures.net/vi...id=292525&nseq=1

 

Rick

Thanks for that clarification, HW. That's interesting, that 6000HP just doesn't hit the sweet spot - a size that's either too big, or else not big enough, for what the railroads need.

 

I suppose going to even larger horsepower engines would present significant problems, too. As discussed earlier, if you have one of those go down, you lose a lot of needed horsepower at once, not to mention the increased possibility of stalled trains. Too many eggs in one basket, with too few options and too little flexibility.

The market for very large horsepower engines may be so limited that it's not worth the development costs to produce them. Just have to see.

Great pictures Rick!

 

But, IMHO, The MK5000's look better that the chisel nosed SD90MAC-H.

 

(and they beat the others to the 5000 hp mark... )

Henry,

 

 

When I first saw MK's 5's years ago, I didn't care for the look of the cab; especially, the long sloped corners; seeing them again... they don't look as bad.

 

Re: the big EMD 80's and 90's... the first wide cab models, those are my favorites.

 

I also like white H 2 version, seen in the link; there's something about that cab style and white paint that works for me.

 

 

Rick